使用DFS生成全排列

#include <string>
#include <cstdio>
#include <cstdlib>
#include <iostream>
#include <algorithm>

using namespace std;

// 使用DFS深度优先搜索生成全排列
// 如果当前生成的排列满足条件（逻辑意义上的有序），返回true
bool dfs(string &bunch, int bLen, string str) {
    if (bLen == str.length()) {
            // 
    }
    
    string::size_type i;
    for (i = 0; i < bLen; ++i) {
        if (!vis[i]) {
            vis[i] = true;
            str += bunch[i];
            if (dfs(bunch, bLen, str)) {
                return true;
            }
            vis[i] = false;
            str = str.substr(0, str.length() - 1);
        }
    }// End of for
    return false;
}

int main() {
    string bunch;
    
    while (cin >> bunch) {
        dfs(bunch, bunch.length(), "");
    }// End of while
    return 0;
}

方法二：使用STL中的next_permutation生成

#include <string>
#include <cstdio>
#include <cstdlib>
#include <iostream>
#include <algorithm>

using namespace std;

string res;

int main() {
    string bunch;
    
    while (cin >> bunch) {
        sort(bunch.begin(), bunch.end());
        do {
            cout << bunch << endl;
        } while (next_permutation(bunch.begin(), bunch.end()));
    }// End of while
    return 0;
}